The objectives of this proposal are summarized as follows: 1. To undertake an inter- and multidisciplinary study of multiple factors which contribute to the etiology of mammary cancer using mouse systems. 2. To investigate the contributions of pharmacogenetics, biochemistry, and endocrinology to the problem of spontaneous and methylcholanthrene- induced mammary tumorigenesis. 3. To investigate biological, biochemical, morphological and endocrinological characteristics of mammary cells, normal and neoplastic, in cell culture. 4. To ultimately serve as a center in the training of medical and graduate students and in the postgraduate continuing education of the practicing physician in the field of oncology in the State of Georgia.